Our insect of the week for April 6, 2026 is Gomphurus externus [ODONATA: Gomphidae], commonly known as the plains clubtail. This species was described in 1858 by Hermann Hagen (a German entomologist who specialized in Neuroptera and Odonata). He accepted a position at Harvard University in 1867 and became the first entomologist in the United States to hold the title, Professor of Entomology.

Plains clubtails prefer moderately moving rivers and large streams with muddy bottoms (sometimes lakes). Adults are often observed in July and August in central Illinois. Adults will consume most soft bodied flying insects (such as mosquitos, other flies, mayflies and more). Nymphs often eat mosquito larvae, other fly lavae, and mayfly nymphs.

Adults often emerge from the numphal stage during the day (most dragonflies perform this metamorphosis at night when there are fewer predators). Nymphs may burrow in the mud of the stream and leave only the tip of their abdomen exposed. They pump water in and out of their abdomen to breathe. Adults prefer warmer temperatures and will often not fly on cloudy or cool summer days.

The specimen in this photograph was collected by our former member, Gordon Adams in Peoria County.